> From: Simon Glass <s...@chromium.org> > Date: Sat, 22 Jan 2022 10:17:10 -0700
Hi Simon, > Hi Mark, > > On Sat, 22 Jan 2022 at 07:12, Mark Kettenis <mark.kette...@xs4all.nl> wrote: > > > > > From: Simon Glass <s...@chromium.org> > > > Date: Fri, 21 Jan 2022 18:40:23 -0700 > > > > > > Hi Mark, > > > > > > On Fri, 14 Jan 2022 at 04:05, Mark Kettenis <kette...@openbsd.org> wrote: > > > > > > > > The power management controller found on Apple SoCs als provides > > > > a way to reset all devices within a power domain. This is needed > > > > to cleanly shutdown the NVMe controller before we hand over > > > > control to the OS. > > > > > > > > Signed-off-by: Mark Kettenis <kette...@openbsd.org> > > > > --- > > > > arch/arm/Kconfig | 1 + > > > > drivers/power/domain/apple-pmgr.c | 73 ++++++++++++++++++++++++++++++- > > > > 2 files changed, 73 insertions(+), 1 deletion(-) > > > > > > This should use devicetree instead of device_bind() and be a reset > > > driver in drivers/reset > > > > Not sure what you mean with "this should use devicetree". The reset > > and power domain functionality is integrated in the same hardware > > register and there is a single node that decsribes the device. > > > > The Linux driver implements the power domain and reset functionality > > in a single driver as well. I suppose I could move the reset code > > into a file of its own in drivers/reset, but I don't think it would > > make the code easier to understand. And I'd still need to bind the > > reset driver explicitly in apple_pmgr_probe() as it isn't possible to > > automatically bind two drivers to a single device tree node as far as > > I can tell. > > It seems odd that Linux does this sort of thing. The normal U-Boot > approach would be to create a parent MFD driver with children for each > uclass. Does linux do that these days? It seems to be common for pinctrl/gpio and clk/reset drivers to be combined in Linux. Not sure if there was a pd/reset combo before the M1 support was accepted, but it is there. MFD is typically used for higher-level functions, i.e. PMIC IC's that include both voltage regulators and an RTC for example. > Driver model cannot create two drivers from one device tree node, > although you can create one manually later as you have done. > > It seems OK to follow along with Linux, if it makes it easier to > maintain. Otherwise, drivers/reset would be better for the reset > driver. > > Either way: > > Reviewed-by: Simon Glass <s...@chromium.org> > Tested on: Macbook Air M1 > Tested-by: Simon Glass <s...@chromium.org> I'll keep it as-is then. Thanks, Mark
